http://www.biochemj.org Biochemical Journal - BJ Energy RSS Feed 0264-6021 1470-8728 Biochemical Journal http://www.biochemj.org/images/bj_Name.gif http://www.biochemj.org http://www.biochemj.org/bj/442/0049/bj4420049.htm Our recent studies suggest that H₂ (hydrogen) has a potential as a novel radioprotector without known toxic side effects. The present study was designed to examine the underlying radioprotective mechanism of H₂ and its protective role on irradiated germ cells. Produced by the Fenton reaction and radiolysis of H₂O, hydroxyl radicals (^•OH) were identified as the free radical species that were reduced by H₂. We used a H₂ microelectrode to dynamically detect H₂ concentration in vivo, and found H₂ significantly reduced in situ fluorescence intensity of hydroxyphenyl fluorescein; however, as we treated the mice with H₂ after irradiation, the decrease is not significant. We found that pre-treatment of H₂ to IR (ionizing radiation) significantly suppressed the reaction of ^•OH and the cellular macromolecules which caused lipid peroxidation, protein carbonyl and oxidatively damaged DNA. The radioprotective effect of H₂ on male germ cells was supported by ameliorated apoptotic findings examined by morphological changes and TUNEL (terminal deoxynucleotidyltransferase-mediated dUTP nick-end labelling) in testicular tissue, and by preserved viability of stem spermatogonia examined for testicular histological parameters, daily sperm production and sperm quality; we used WR-2721 [S-2-(3-aminopropylamino)ethyl phosphorothioic acid] as a reference compound. Our results represent the first in vivo evidence in support of a radioprotective role of H₂ by neutralizing ^•OH in irradiated tissue with no side effects.

]]> Yunhai Chuai, Fu Gao, Bailong Li, Luqian Zhao, Liren Qian, Fei Cao, Lei Wang, Xuejun Sun, Jianguo Cui and Jianming Cai 2012-02-15 doi:10.1042/BJ20111786 Portland Press Ltd. 2012-02-15 http://www.biochemj.org/bj/442/0191/bj4420191.htm S-nitrosothiols are products of nitric oxide (NO) metabolism that have been implicated in a plethora of signalling processes. However, mechanisms of S-nitrosothiol formation in biological systems are uncertain, and no efficient protein-mediated process has been identified. Recently, we observed that ferric cytochrome c can promote S-nitrosoglutathione formation from NO and glutathione by acting as an electron acceptor under anaerobic conditions. In the present study, we show that this mechanism is also robust under oxygenated conditions, that cytochrome c can promote protein S-nitrosation via a transnitrosation reaction and that cell lysate depleted of cytochrome c exhibits a lower capacity to synthesize S-nitrosothiols. Importantly, we also demonstrate that this mechanism is functional in living cells. Lower S-nitrosothiol synthesis activity, from donor and nitric oxide synthase-generated NO, was found in cytochrome c-deficient mouse embryonic cells as compared with wild-type controls. Taken together, these data point to cytochrome c as a biological mediator of protein S-nitrosation in cells. This is the most efficient and concerted mechanism of S-nitrosothiol formation reported so far.

]]> Katarzyna A. Broniowska, Agnes Keszler, Swati Basu, Daniel B. Kim‑Shapiro and Neil Hogg 2012-02-15 doi:10.1042/BJ20111294 c-mediated formation of S-nitrosothiol in cells]]> Portland Press Ltd. 2012-02-15